Predictions for Hadronic Yields at 5.52 TeV Pb+Pb

B. Lukács and A. Ster

+ many, back to 1987 as

History

• J. Zimányi and A. Rácz• H-W. Barz• T. S. Biró• L. P. Csernai• T. Csörgő• B. Jakobsson• B. Kämpfer• Gy. Kuti• P. Lévai• K. Martinás• L. Polonyi• K. Szlachányi• Gy. Wolf

Rehadronisation Models

• #1-#8: (Gluon Fragmentation; Final Hadronic Masses; Final State Compressibility) 0: No, 1: Yes with Weight 1 as Binary +1

• #9: No Quark Phase At All

• #10: Sequential Fission

• #11: As #7 but with Maximal Possible Gluon Fragmentation (weight 1.36)

E/N vs. S/N, Pb+Pb

Figure is direct calculation. For the upper 4 points a logarithmic fit is excellent, expected as ultrarelativistic: S/N=47.019+2.168*ln(Ecm/A, GeV)±0.14. See Table.

Rehadronisation, Xi/N

Rehadronisation, Xi/N, low S/N

Successes/failures at SPS/RHIC

Notes

• These are χ² mean deviations for measured ratios. It seems that until SPS energies #9 is the best; for RHIC #7 is the best, #5 is close second, but simple averaging does not help.

Checks for SPS/RHIC energies; ratios used

Model predictions, u & d are not yet distinguished

Model deviations from conservations + efficiency of transferring the kinetic

energy

#7 is quite good for conservation; efficiency is 0.5 %.

Quark charges/spins considered

• Total starting quarks: u=578, d=664, s=0,

• Antiquarks 0. Final state masses & gluon fragmentation are u/d symmetric. Models: random u/d selection from common pool.

Taking charge into consideration; results

Various mispredictions and a 2.76 TeV/A

preliminary

PROBLEMS

For RHIC energies pions are overabundant; probable reason hadronosation into resonances. It seems that it was cca. 50 % for 200 GeV. For 2.76 TeV Ω yield is geometric mean of #7 & #5. Otherwise…